- Buyer's Guide
The other day while waiting at an airport, I noticed a couple of teenagers playing speed chess, also known as lightning chess. According to the rules, a game of 40 moves or less must be played in fewer than six minutes (three minutes per side). Their hands and pieces were in constant motion. It seemed to be more a foot race than a game of wit, intellect and strategy. Yet these kids couldn't seem to get enough of it, as they were playing one game after another.
How does this relate to lubrication and maintenance? In my view, the most important maintenance function doesn't require anything from the tool box. It doesn't require an instrument or an oil sample. It may not be on your PM schedule or lube route. What it requires instead are skillful inspections that are rapid, comprehensive and frequent. Taking a pointer from speed chess, we need to pick up both inspection tempo and quality by deploying sensory-based (versus instrument-based) condition monitoring techniques. Let's call them daily OMIs, or one-minute inspections.
Learning Machine "Sign Language"
Begin by learning how lubricants and machines reveal problems. Unlike people who have verbal skills, machines use "sign language" to communicate what hurts or what has invaded their system. Recognizing the "signs" or symptoms that the machine conveys is a required skill for those who work with machines and are responsible for their care and feeding. This involves training, practice and motivation.
Many PMs are inspections; however, they are often performed without the required skills, motivation and frequency. In contrast, daily OMIs are critical, high-resolution snapshots of machine and lubricant condition. Such inspections need to be conducted by trained operators, technicians, millwrights or others who have frequent access to machines. As is often said for safety, quality and total productive maintenance (TPM) - machine reliability is everyone's responsibility.
Checklists are helpful when completing tasks. These can be incorporated into scheduling software, maintenance PDAs and even posted on or near the machine itself. The range of inspections will vary considerably depending on the machine type and how it has been accessorized for inspection activities. Below is a basic list of common lubrication-related inspection tasks, many of which have been discussed previously in Noria publications:
Temperature. Use touch, gauges and/or heat guns to inspect for general or localized hot running conditions. Besides a host of mechanical explanations, temperature excursions can also be caused by wrong lubricant, degraded lubricant, contaminated lubricant, aeration, varnish, etc.
Oil Volume. Use level gauges, sight glasses, dip sticks or inspection ports/hatches. A slight drift in oil level (up or down) can be a critical alarm.
Pressure. Use gauges or pressure transducers at multiple points as needed. Temperature, viscosity, flow restrictions and aeration are among the many causes of pressure changes.
Filter. Examine delta-P gauges and bypass indicators to confirm filter is serviceable. When filters plug prematurely, there's usually an important reason why.
BS&W. Take bottom samples or examine bottom, sediment and water (BS&W) bowls for abnormal accumulations such as sludge, wear debris, free water, biomass and other contaminants.
Ventilation. Confirm serviceable condition of breathers and inspect for abnormal fumes, vapor and smoke.
Clear and Bright. Pull samples or inspect oil sight glasses, BS&W bowls and bottle oilers for oil color, clarity, insolubles, suspensions, aeration/ foam, emulsions, fouling, etc.
Leakage. Use a powerful flashlight to inspect shaft seals, gaskets, actuators seals, fittings, unions, ports, hoses, etc. Sudden leakage at multiple points is often caused by a change in lubricant quality.
Fluid Surface and Headspace. Through inspection hatches and ports look for foam, varnish, sludge, bathtub rings, corrosion and churning.
Points of Entry. Inspect for potential ingression sites such as unsealed or unprotected vents, breathers, hatches, inspection ports, clean-out covers, etc.
Dirty Exterior. Machines that are dirty on the outside are usually dirty on the inside as well. Keeping machines wiped down and clean is a precursor to contamination control.
Spits and Sputters. Machines emit an assortment of audible signals; some are normal but other are not. Report abnormal whines, rattles, rumbles, pops, etc. Use a rod, garden hose or stethoscope as needed to localize the generating source.
Grease Condition/Color. Inspect grease extruding from seals and along shafts for abnormal color, consistency and condition.
The central theme of the daily OMI is the need for inspection vigilance, quality and scope. With oil analysis, we often say "you can't catch a fish unless your hook's in the water". This refers to the need to frequently sample oil if you expect to catch nonconforming conditions or machine faults. We've also learned that having your hook in the water is not enough either. We need to have it baited correctly and know how and where to fish. The same wise advice applies to machine inspections.
By getting into the habit of doing daily OMIs with a sharp and skillful eye, you can probably catch more problems than oil analysis, vibration analysis and thermography combined.